Wafer chamfering method and apparatus

ABSTRACT

A wafer to be chamfered is supported in such a manner as to rotate and to move in the X-axis direction and the Y-axis direction which are perpendicular to one another, and a periphery grinding wheel is rotatably placed on the Y-axis. To chamfer a circular part of the wafer, the circular part of the wafer is pressed against the rotating periphery grinding wheel, and then, the wafer is rotated. To chamfer an orientation flat of the wafer, the orientation flat of the wafer is pressed against the rotating periphery grinding wheel, and then, the wafer is fed in the X-axis direction.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a wafer chamfering method andapparatus, and more particularly to a wafer chamfering method andapparatus for chamfering a wafer in which an orientation flat or a notchis formed at the periphery thereof.

2. Description of Related Art

A conventional wafer chamfering apparatus is constructed in such a waythat a wafer table, on which a wafer to be chamfered is mounted, issupported in a manner to move along the Y-axis, and that a peripherygrinding wheel is placed on the Y-axis.

To chamfer a circular part of the wafer by the above-mentionedchamfering apparatus, the circular part of the wafer is pressed againstthe rotating periphery grinding wheel. To chamfer an orientation flatpart of the wafer, the orientation flat part of the wafer is pressedagainst the rotating periphery grinding wheel, and the wafer is slightlyrotated and is slightly fed along the Y-axis, so that the orientationflat part can be chamfered.

A notch part of a wafer with the notch is chamfered in the same manner.The notch part of the wafer is pressed against a rotating notch grindingtool, and the wafer is slightly rotated and is slightly fed along theY-axis, so that the notch part can be chamfered.

In the above-mentioned conventional chamfering method, it is extremelydifficult to control the movement and rotation of the wafer, when theorientation flat part or the notch part is chamfered. Thus, thestraightness of the orientation flat part or the notch part becomesdeteriorated.

SUMMARY OF THE INVENTION

The present invention has been developed in view of the above-describedcircumstances, and has as its object the provision of a wafer chamferingmethod and apparatus for accurately chamfering the wafer which has theorientation flat or the notch at the periphery thereof.

To achieve the above-mentioned object, the wafer chamfering method ofthe present invention for chamfering a periphery of a wafer which has acircular part, an orientation flat part and orientation flat cornerparts, wherein the wafer is supported in such a manner as to rotate andto move in an X-axis direction and a Y-axis direction which areperpendicular to one another, a periphery grinding wheel is rotatablyplaced on the Y-axis, comprises the steps of: chamfering the circularpart of the wafer by bringing the circular part into contact with theperiphery grinding wheel, which is rotating, and by rotating the wafer;chamfering the orientation flat part of the wafer by bringing theorientation flat part into contact with the periphery grinding wheel,which is rotating, and by feeding the wafer in the X-axis direction; andchamfering one of the orientation flat corner parts of the wafer bybringing the one of the orientation flat corner parts into contact withthe periphery grinding wheel, which is rotating, and by rotating thewafer and feeding the wafer in the X-axis direction and the Y-axisdirection so that the one of the orientation flat corner parts canalways be in contact with the periphery grinding wheel.

According to the present invention, the wafer is supported in such amanner as to rotate and to move in the X-axis direction and the Y-axisdirection which are perpendicular to one another, and the peripherygrinding wheel is rotatably placed on the Y-axis. To chamfer thecircular part of the wafer, the circular part is pressed against therotating periphery grinding wheel, and then the wafer is rotated. Tochamfer the orientation flat part of the wafer, the orientation flat ispressed against the rotating periphery grinding wheel, and then thewafer is fed in the X-axis direction. To chamfer each of the orientationflat corner parts of the wafer, the orientation flat corner part ispressed against the rotating periphery grinding wheel, and then, thewafer is rotated and is fed in the X-axis direction and the Y-axisdirection so that the orientation flat corner part can always be incontact with the periphery grinding wheel.

To achieve the above-mentioned object, a wafer chamfering method of thepresent invention for chamfering a periphery of a wafer which has acircular part, a notch part and notch corner parts, wherein the wafer issupported in such a manner as to rotate and to move in an X-axisdirection and a Y-axis direction which are perpendicular to one another,a periphery grinding wheel and a notch grinding tool are rotatablyplaced on the Y-axis, comprises the steps of: chamfering the circularpart of the wafer by bringing the circular part into contact with theperiphery grinding wheel, which is rotating, and by rotating the wafer;chamfering the notch part of the wafer by bringing the notch part intocontact with the notch grinding tool, which is rotating, and by feedingthe wafer in the X-axis direction and the Y-axis direction so that thenotch part can always be in contact with the notch grinding tool; andchamfering one of the notch corner parts of the wafer by bringing theone of the notch corner parts into contact with the notch grinding tool,which is rotating, and by feeding the wafer in the X-axis direction andthe Y-axis direction so that the one of the notch corner parts canalways be in contact with the notch grinding tool.

According to the present invention, the wafer is supported in such amanner as to rotate and to move in the X-axis direction and the Y-axisdirection which are perpendicular to one another, and the peripherygrinding wheel and the notch grinding tool are rotatably placed on theY-axis. To chamfer the circular part of the wafer, the circular part ispressed against the rotating periphery grinding wheel, and then thewafer is rotated. To chamfer the notch part of the wafer, the notch partis pressed against the rotating notch grinding tool, and then the waferis fed in the X-axis direction and the Y-axis direction so that thenotch part can always be in contact with the notch grinding tool. Tochamfer each of the notch corner parts of the wafer, the notch cornerpart is pressed against the rotating notch grinding tool, and then, thewafer is fed in the X-axis direction and the Y-axis direction so thatthe notch corner part can always be in contact with the notch grindingtool.

BRIEF DESCRIPTION OF THE DRAWINGS

The nature of this invention, as well as other objects and advantagesthereof, will be explained in the following with reference to theaccompanying drawings, in which like reference characters designate thesame or similar parts throughout the figures and wherein:

FIG. 1 is a side view illustrating an embodiment of a wafer chamferingapparatus according to the present invention;

FIG. 2 is a plan view illustrating a wafer feeding apparatus;

FIG. 3 is a view taken along a line A--A of FIG. 2;

FIGS. 4(a), 4(b), 4(c), 4(d), 4(e) and 4(f) are views of assistance inexplaining a method of chamfering a wafer with an orientation flat; and

FIGS. 5(a), 5(b), 5(c), 5(d) and 5(e) are views of assistance inexplaining a method of chamfering a wafer with a notch.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

This invention will be described in further detail by way of examplewith reference to the accompanying drawings.

FIG. 1 is a side view illustrating an embodiment of a wafer chamferingapparatus according to the present invention. As shown in FIG. 1, thewafer chamfering apparatus 10 comprises a wafer feeding apparatus 12 anda grinding tool apparatus 14.

A description will be given of the construction of the wafer feedingapparatus 12. As shown in FIGS. 1-3, a pair of guide rails 18 isprovided on a horizontally-arranged base 16. A Y-axis table 22 isslidably supported on the guide rails 18 via sliders 20. The Y-axistable 22 is driven by a feed screw mechanism, which is constructed asdescribed below.

As shown in FIG. 2, a ball screw 24 is provided in parallel with theguide rails 18 on the base 16. The ball screw 24 is engaged with a nutmember 26, which is secured to the Y-axis table 22. One end of the ballscrew 24 connects to a motor 28, which is rotatable forward and backwardand is driven to rotate the ball screw 24. When the ball screw 24rotates, the nut member 26 moves along the ball screw 24, and thereby,the Y-axis table 22, which is connected to the nut member 26, slidesalong the guide rails 18. A direction in which the Y-axis table 22slides will hereafter be referred to as a Y-axis direction, and astraight line which is parallel with the Y-direction and goes throughthe center of the Y-axis table 22 will be referred to as the Y-axis.

A pair of guide rails 30 is provided on the Y-axis table 22 in adirection perpendicular to the Y-axis direction. An X-axis table 34 isslidably supported on the guide rails 30 via sliders 32. The X-axistable 34 is driven by a feed screw mechanism in the same manner as theY-axis table 22, and the feed screw mechanism is constructed asdescribed below.

As shown in FIG. 2, a ball screw 36 is provided in parallel with theguide rails 30 on the Y-axis table 22. The ball screw 36 is engaged witha nut member 38, which is secured to the X-axis table 34. One end of theball screw 36 connects to a motor 40, which is rotatable forward andbackward and is driven to rotate the ball screw 36. When the ball screw36 rotates, the nut member 38 moves along the ball screw 36, andthereby, the X-axis table 34, which is connected to the nut member 34,slides along the guide rails 30. A direction in which the X-axis table34 slides will hereafter be referred to as an X-axis direction, and astraight line which is parallel with the X-axis direction and goesthrough the center of the X-axis table 34 will be referred to as theX-axis.

A wafer table support 42 is centered on the X-axis table 34. A wafertable 44 is rotatably supported on the wafer table support 42, and thewafer table 44 is rotated by a motor (not shown), which is built in thewafer table support 42. A wafer W to be chamfered is held on the wafertable 44 with vacuum. A straight line which is perpendicular to thewafer table 44 and goes through the rotational center of the wafer table44 will be referred to as the θ-axis.

Since the wafer feeding apparatus 12 is constructed as described above,the wafer W held on the wafer table 44 can be rotated about the θ-axisand can be fed in the X-axis direction and the Y-axis direction.

A description will be given of the construction of the grinding toolapparatus 14. As shown in FIG. 1, the grinding tool apparatus 14 has agrinding tool support 46. The grinding tool support 46 is slidablysupported on a column (not shown), which vertically stands on the base16, and a drive (not shown) drives the grinding tool support 46 so thatthe grinding tool support 46 moves up and down along the column. Aperiphery grinding wheel 48 and a notch grinding tool 50 are provided atthe bottom of the grinding tool support 46. The periphery grinding wheel48 and the notch grinding tool 50 are respectively rotated by motors(not shown), which are built in the grinding tool support 46. Theperiphery grinding wheel 48 and the notch grinding tool 50 are locatedon the Y-axis as shown in FIG. 2, and the notch grinding tool 50 islocated at a predetermined height above the periphery grinding wheel 48as shown in FIG. 1.

The grinding tool apparatus 14 is constructed as described above, andthe periphery of the wafer W is chamfered in such a way that theperiphery of the wafer W is pressed against the rotating peripherygrinding wheel 48 or the rotating notch grinding tool 50 of the grindingtool apparatus 14.

The wafer chamfering apparatus 10 of the present invention isconstructed as described above, and a controller (not shown) controlsthe wafer chamfering apparatus 10.

A description will be given of the operation of the wafer chamferingapparatus 10 according to the present invention, which is constructed inthe above-mentioned manner. Since the wafer chamfering apparatus 10 isable to chamfer both the wafer W with an orientation flat and the waferW with a notch, a description will be given first of the method forchamfering the wafer W with the orientation flat, and then a descriptionwill be given of the method for chamfering the wafer W with the notch.

A description will hereunder be given of the method for chamfering thewafer W with the orientation flat with reference to FIGS. 4(a)-4(f),which describe the procedure.

First, the wafer W is set on the wafer chamfering apparatus 10.Specifically, the wafer W is positioned on the wafer table 44, and thewafer W is held on the wafer table 44 with vacuum.

The wafer W is placed so that the center thereof can be positioned onthe θ-axis of the wafer table 44, and that an orientation flat OFthereof can be parallel to the Y-axis (see FIG. 4(a)). This state willbe referred to as an initial state, where the center of the wafer W ispositioned on the Y-axis and at a predetermined distance away from theaxis of the periphery grinding wheel 48.

On the other hand, in the grinding tool apparatus 14, the grinding toolsupport 46 moves up or down so as to position the periphery grindingwheel 48 at a predetermined machining position.

On completion of the above-mentioned initialization, the waferchamfering apparatus 10 starts chamfering the wafer W.

First, the periphery grinding wheel 48 is rotated, and the wafer W isfed in the Y-axis direction to the periphery grinding wheel 48 at thesame time. When the wafer W moves by a predetermined distance, acircular part C of the wafer W meets the rotating periphery grindingwheel 48, and the wafer W stops moving.

As shown in FIG. 4(a), when the circular part C of the wafer W meets theperiphery grinding wheel 48, the wafer W starts rotating about theθ-axis by a predetermined angle. Thereby, the circular part C of thewafer W is chamfered by the rotating periphery grinding wheel 48.

As shown in FIG. 4(b), when the wafer W rotates by the predeterminedangle, a point of contact between the wafer W and the periphery grindingwheel 48 reaches an orientation flat corner OR of the wafer W. In thisstate, only the rotation of the wafer W cannot bring the orientationflat corner OR into contact with the periphery grinding wheel 48. Forthis reason, the orientation flat corner OR is chamfered by controllingmovement of the wafer W as described below.

When the point of contact reaches the orientation flat corner OR of thewafer W as represented with a broken line in FIG. 4(c), the wafer W isrotated about the θ-axis and is fed in the X-axis direction and theY-axis direction. The wafer W moves so that the orientation flat cornerOR can always be in contact with the periphery grinding wheel 48. Thus,the orientation flat corner OR of the wafer W is chamfered by theperiphery grinding wheel 48.

Then, the orientation flat OF of the wafer W, of which movement iscontrolled as stated above, finally becomes parallel to the X-axis asrepresented with a solid line in FIG. 4(c), and the chamfering of theorientation flat corner OR is completed. In this state, the peripherygrinding wheel 48 is in contact with the orientation flat OF of thewafer W. Then, the orientation flat OF is chamfered subsequently.

As shown in FIG. 4(d), the orientation flat OF is chamfered by feedingthe wafer W in the X-axis direction. That is, the wafer W moves inparallel with the orientation flat OF while the orientation flat OFbeing in contact with the periphery grinding wheel 48. Thereby, theorientation flat OF is chamfered by the periphery grinding wheel 48.

The wafer W is fed in the X-axis direction until the point of contactbetween the wafer W and the periphery grinding wheel 48 reaches theother end of the orientation flat OF, or the other orientation flatcorner OR as shown in FIG. 4(e). When the point of contact reaches theorientation corner OR, the orientation flat corner OR is chamferedsubsequently.

Specifically, when the point of contact reaches the orientation flatcorner OR of the wafer W as represented with a solid line in FIG. 4(f),the wafer W is rotated about the θ-axis and is fed in the X-axisdirection and the Y-axis direction. The wafer W moves so that theorientation flat corner OR can always be in contact with the peripherygrinding wheel 48. Thus, the orientation flat corner OR of the wafer Wis chamfered by the periphery grinding wheel 48.

Then, the center of the wafer W, of which movement is controlled asstated above, is finally positioned on the Y-axis as represented with abroken line in FIG. 4(f), and the chamfering of the orientation flatcorner OR is completed. In this state, the periphery grinding wheel 48is in contact with the circular part C of the wafer W. Thereafter, thewafer W is rotated about the θ-axis to chamfer the circular part Csubsequently, and then, the wafer W returns to the state where thechamfering is started, that is, the state shown in FIG. 4(a). Thechamfering of the whole periphery of the wafer W is completed byrepeating the above-mentioned series of processes a plurality of times.

When the chamfering of the wafer W is completed, the wafer W stops inthe state where the chamfering started, that is, the state shown in FIG.4(a). Then, the wafer W moves in the Y-axis direction so that it becomesfarther away from the periphery grinding wheel 48, and the wafer Wreturns to the initial state. The wafer W is picked from the wafer table44, and the machining is completed.

As stated above, according to the wafer chamfering method and apparatusin this embodiment, when the orientation flat OF of the wafer W ischamfered, the wafer W is fed straight in parallel with the orientationflat OF. Thus, it is possible to easily chamfer the orientation flat OFwith high straightness. When each of the orientation flat corners OR ofthe wafer W is chamfered, the wafer W is moved so that the orientationflat corner OR can always be in contact with the periphery grindingwheel 48. Thus, it is possible to easily chamfer the orientation flatcorners OR with high accuracy. Moreover, it is possible to controlmovement of the wafer W in a simple way.

In this embodiment, the whole periphery of the wafer W is sequentiallychamfered, but each part of the periphery of the wafer W may bechamfered separately. Specifically, only the circular part C of thewafer W may be chamfered first, then the orientation flat F may bechamfered, and finally the orientation flat corners OR may be chamfered.

The machining order should not be restricted to the above-mentionedorder. For instance, the orientation flat OF may be chamfered first,then the orientation flat corners OR may be chamfered, and finally thecircular part C may be chamfered.

A description will be given of the method for chamfering the wafer Wwith the notch with reference to FIGS. 5(a)-5(e), which describe theprocedure.

First, the wafer W is set on the wafer chamfering apparatus 10.Specifically, the wafer W is positioned on the wafer table 44, and thewafer W is held on the wafer table 44 with vacuum.

The wafer W is placed so that the center thereof can be positioned onthe θ-axis of the wafer table 44, and that a notch NO thereof can bepositioned on the X-axis (see FIG. 5(a)). This state will be referred toas an initial state, where the center of the wafer W is positioned onthe Y-axis and at a predetermined distance away from the axis of theperiphery grinding wheel 48.

On the other hand, in the grinding tool apparatus 14, the grinding toolsupport 46 moves up or down so as to position the periphery grindingwheel 48 at a predetermined machining position.

On completion of the above-mentioned initialization, the waferchamfering apparatus 10 starts chamfering the wafer W.

First, the periphery grinding wheel 48 is rotated, and the wafer W isfed in the Y-axis direction to the periphery grinding wheel 48 at thesame time. When the wafer W moves by a predetermined distance, acircular part C of the wafer W meets the rotating periphery grindingwheel 48, and the wafer W stops moving.

As shown in FIG. 5(a), when the circular part C of the wafer W meets theperiphery grinding wheel 48, the wafer W starts rotating. Thereby, thecircular part C of the wafer W is chamfered by the rotating peripherygrinding wheel 48 as shown in FIG. 5(b).

After the wafer W rotates a predetermined number of times, thechamfering of the circular part C of the wafer W is completed. Then, thewafer W stops rotating, and returns to the initial state. Thereafter,the wafer chamfering apparatus 10 starts chamfering the notch NO of thewafer W.

To chamfer the notch NO, the wafer W moves in the X-axis direction by apredetermined distance from the initial state until it reaches apredetermined machining position (see FIG. 5(c)). On the other hand, inthe grinding tool apparatus 14, the grinding tool support 46 moves downby a predetermined distance so that the notch grinding tool 50 can bepositioned at a predetermined machining position. Then, the notchgrinding tool 50 is rotated, and the wafer W is fed in the Y-axisdirection at the same time. When the wafer W moves by a predetermineddistance, a notch corner NR of the wafer W meets the rotating notchgrinding tool 50, and the wafer W stops moving.

As shown in FIG. 5(c), when the notch corner NR of the wafer W meets thenotch grinding tool 50, the wafer W is fed in the X-axis direction andthe Y-axis direction so that the notch corner NR can be chamfered. Inother words, the wafer W moves according to the shape of the notchcorner NR so that the notch corner NR can always be in contact with thenotch grinding tool 50. Thereby, the notch corner NR of the wafer W ischamfered by the notch grinding tool 50.

After the notch corner NR is chamfered, the wafer W is subsequently fedin the X-axis direction and the Y-axis direction so that the notch NOcan be chamfered. Specifically, as shown in FIG. 5(d), the wafer W isfed so that the notch NO can always be in contact with the notchgrinding tool 50. In FIG. 5(d), the notch NO is V-shaped for example,and the wafer W moves in a manner to describe V according to the shapeof the notch NO. Thereby, the notch NO of the wafer W is chamfered bythe notch grinding tool 50.

When a point of contact between the wafer W and the notch grinding tool50 reaches the other notch corner NR at the other side of the notch NO,the notch corner NR is subsequently chamfered as shown in FIG. 5(e).Specifically, the wafer W is fed in the X-axis direction and the Y-axisdirection so that the notch corner NR can always be in contact with thenotch grinding tool 50. Thereby, the notch corner NR of the wafer W ischamfered by the notch grinding tool 50.

After the notch corner NR at the other side is chamfered, the wafer Wstops moving. Then, the notch NO and the notch corners NR are chamferedin the reverse direction in the same manner as described above.Specifically, the notch grinding tool 50 moves relatively to the wafer Wfrom the notch corner NR at the other side to the notch NO, and itreturns to the state where the chamfering of the notch NO started, thatis, the state shown in FIG. 5(c).

The chamfering of the notch NO and the notch corners NR is completed byrepeating the above-mentioned series of processes a required number oftimes.

When the chamfering of the notch NO and the notch corners NR iscompleted, the wafer W stops in the state where the chamfering of thenotch NO started, that is, the state shown in FIG. 5(c). Then, the waferW moves in the Y-axis direction so that it becomes farther away from thenotch grinding tool 50, and the wafer W returns to the initial state.The wafer W is picked from the table 44, and the machining is completed.

As stated above, according to the wafer chamfering method and apparatusin this embodiment, when the notch NO of the wafer W is chamfered, thewafer W is fed so that the notch grinding tool 50 can always be incontact with the notch NO. Thus, it is possible to easily chamfer thenotch NO with high accuracy. When each of the notch corners NR of thewafer W is chamfered, the wafer W is fed so that the notch grinding tool50 can always be in contact with the notch corner NR. Thus, it ispossible to easily chamfer the notch corners NR with high accuracy.Moreover, it is possible to control movement of the wafer W in a simpleway.

In this embodiment, the circular part C of the wafer W is chamferedfirst, and then the notch NO and the notch corners NR are chamfered. Themachining order, however, should not be restricted to this: for example,the notch NO and the notch corners NR may be chamfered first, and thenthe circular part C may be chamfered.

As set forth hereinabove, according to the present invention, themovement of the wafer is controlled by rotating the wafer on therotational axis and feeding the wafer along the two axes which areperpendicular to the rotational axis and are perpendicular to oneanother. Thus, it is possible to accurately chamfer the whole peripheryof the wafer which has the orientation flat or the notch at theperiphery thereof.

It should be understood, however, that there is no intention to limitthe invention to the specific forms disclosed, but on the contrary, theinvention is to cover all modifications, alternate constructions andequivalents falling within the spirit and scope of the invention asexpressed in the appended claims.

We claim:
 1. A wafer chamfering method for chamfering a periphery of awafer which has a circular part, an orientation flat part andorientation flat corner parts, wherein the wafer is supported in such amanner as to rotate and to move in an X-axis direction and a Y-axisdirection which are perpendicular to one another in a horizontal plane,a periphery grinding wheel is rotatable about a vertical axis whichintersects the Y-axis, said wafer chamfering method comprising the stepsof:chamfering the circular part of the wafer by bringing the circularpart along the Y-axis into contact with said periphery grinding wheelwhich is rotating, and by rotating the wafer; chamfering the orientationflat part of the wafer by bringing the orientation flat part along theY-axis into contact with said periphery grinding wheel which isrotating, and by feeding the wafer in the X-axis direction; andchamfering one of the orientation flat corner parts of the wafer bybringing the one of the orientation flat corner parts into contact withsaid periphery grinding wheel, which is rotating, and by rotating thewafer and feeding the wafer in the X-axis direction and the Y-axisdirection so that the one of the orientation flat corner parts canalways be in contact with said periphery grinding wheel.
 2. A waferchamfering apparatus for chamfering a periphery of a wafer which has acircular part, an orientation flat part and orientation flat cornerparts, said wafer chamfering apparatus comprising:a wafer table supportwhich is capable of moving in an X-axis direction and a Y-axis directionwhich are perpendicular to one another in a horizontal plane; a wafertable which is rotatably placed on said wafer table support and holdsthe wafer; a grinding tool support which is positioned on the Y-axis andis capable of moving up and down perpendicular to said Y-axis; aperiphery grinding wheel which is rotatably placed on said grinding toolsupport; a controller which controls feeding of said wafer table supportin the X-axis direction and the Y-axis direction, rotation of said wafertable, up-and-down movement of said grinding tool support, and rotationof said periphery grinding wheel; wherein said controller brings thecircular part of the wafer along the Y-axis into contact with saidperiphery grinding wheel, which is rotating, and rotates the wafer,thereby chamfering the circular part; said controller brings theorientation flat part of the wafer along the Y-axis into contact withsaid periphery grinding wheel, which is rotating, and feeds the wafer inthe X-axis direction, thereby chamfering the orientation flat part; andsaid controller brings one of the orientation flat corner parts of thewafer into contact with said periphery grinding wheel, which isrotating, and rotates the wafer and feeds the wafer in the X-axisdirection and the Y-axis direction so that the one of the orientationflat corner parts can always be in contact with said periphery grindingwheel, thereby chamfering the one of the orientation flat corner parts.3. A wafer chamfering method for chamfering a periphery of a wafer whichhas a circular part, a notch part and notch corner parts, wherein thewafer is supported in such a manner as to rotate and to move in anX-axis direction and a Y-axis direction which are perpendicular to oneanother in a horizontal plane, a periphery grinding wheel and a notchgrinding tool are rotatable about a vertical axis which intersects theY-axis, said wafer chamfering method comprising the steps of:chamferingthe circular part of the wafer by bringing the circular part along theY-axis into contact with said periphery grinding wheel, which isrotating, and by rotating the wafer; chamfering the notch part of thewafer by bringing the notch part along the Y-axis into contact with saidnotch grinding tool, which is rotating, and by feeding the wafer in theX-axis direction and the Y-axis direction so that the notch part canalways be in contact with said notch grinding tool; and chamfering oneof the notch corner parts of the wafer by bringing the one of the notchcorner parts alone the Y-axis into contact with said notch grindingtool, which is rotating, and by feeding the wafer in the X-axisdirection and the Y-axis direction so that the one of the notch cornerparts can always be in contact with said notch grinding tool.
 4. A waferchamfering apparatus for chamfering a periphery of a wafer which has acircular part, a notch part and notch corner parts, said waferchamfering apparatus comprising:a wafer table support which is capableof moving in an X-axis direction and a Y-axis direction which areperpendicular to one another in a horizontal plane; a wafer table whichis rotatably placed on said wafer table support and holds the wafer; agrinding tool support which is positioned on the Y-axis and is capableof moving up and down perpendicular to said Y-axis; a periphery grindingwheel which is rotatably placed on said grinding tool support; a notchgrinding tool which is rotatably placed on said grinding tool support; acontroller which controls feeding of said wafer table support in theX-axis direction and the Y-axis direction, rotation of said wafer table,up-and-down movement of said grinding tool support, rotation of saidperiphery grinding wheel, and rotation of said notch grinding tool;wherein said controller brings the circular part of the wafer along theY-axis into contact with said periphery grinding wheel, which isrotating, and rotates the wafer, thereby chamfering the circular part;said controller bring the notch part of the wafer along the Y-axis intocontact with said notch grinding tool, which is rotating, and feeds thewafer in the X-axis direction and the Y-axis direction so that the notchpart can always be in contact with said notch grinding tool, therebychamfering the notch part; and said controller brings one of the notchcorner parts of the wafer along the Y-axis into contact with said notchgrinding tool, which is rotating, and feeds the wafer in the X-axisdirection and the Y-axis direction so that the one of the notch cornerparts can always be in contact with said notch grinding tool, therebychamfering the one of the notch corner parts.